1. Field of the Invention
The present invention generally relates to a transformer and to a cassette library system having the transformer. More particularly, the present invention relates to techniques for reducing the thickness and the number of parts of a transformer without lowering the sensitivity thereof.
2. Description of the Related Art
Some conventional recording medium cassettes each include an internal memory for storing various kinds of information on the recording medium cassette, for example, a date of manufacture, a manufacturing factory, a title of information recorded on a corresponding recording medium, the name of a file recorded thereon, the specifications and usage conditions thereof, recording locations thereon, or information represented by information signals recorded thereon.
The recording medium cassettes each including such an inner memory are used in, for instance, a cassette library system adapted so that many recording medium cassettes are contained in an accommodating rack and that, if a certain recording medium cassette is required, the required recording medium cassette is taken out of the accommodating rack by a cassette transfer mechanism and then used.
There have been two types of methods for reading information from and writing information to the internal memory included in the recording medium cassette. One is a contact type method, according to which information is read from and written to the internal memory are performed by, for example, bringing an external terminal connected to the internal memory of the recording medium cassette into contact with a connector of a read/write mechanism for performing such read/write operations. The other is a non-contact method, according to which such read/write operations are performed are performed by, for instance, a transformer provided in the read/write mechanism.
FIGS. 17 and 18 show a conventional transformer provided in such a read/write mechanism. Incidentally, this read/write mechanism is adapted to be able to perform both of the contact type method and the non-contact type method of reading information from and writing information to the internal memory.
The transformer a is constituted by coupling a rectangular communication portion b with a connecting portion c placed under this communication portion b. The communication portion b is formed as a multi-layer substrate constituted by connecting a plurality of substrates d, d, . . . , d. The base material of the communication portion b is, for instance, an epoxy resin material.
The connecting portion c is formed by a flexible printed substrate, an end of which is connected to the bottom of one of the substrates d of the communication portion b.
In the transformer a, a predetermined circuit pattern e is formed over the communication portion b and the connecting portion c. A part of this circuit pattern e is formed as a transformer circuit f. This transformer circuit f consists of a coil part g formed like a coil in the connecting portion b and first connection parts h, h respectively connected to both ends of the coil part g. Further, the transformer circuit f is formed by conducting end portions of circuits each formed like a coil on the substrates d, d, . . . d through, for example, through-holes i, i, . . . , i.
In the circuit patterns e, parts j, j, . . . , j, other than parts of the transformer circuits f are formed as second connection parts. An end portion of each of these second connection parts j, j, . . . , j is connected to a corresponding one of lands k, k, . . . , k formed at the bottom portion of the communication portion b.
Both ends of the transformer circuit f and the other end of each of the second connection parts j, j, . . . , j are positioned at connector portions (not shown) provided at the side, which is not connected to the communication portion b, of the connecting portion c. These connector portions are connected to a drive-unit-side connector m provided on the bottom surface of a circuit board of the drive unit (see FIG. 18).
The communication portion b is attached to a holder n having an L-shaped longitudinal section. The holder n consists of a vertical portion o and a horizontal portion p projecting from the bottom edge of the vertical portion o. These portions o and p are formed in such a manner as to be integral with each other. The holder n is rotatably supported by a supporting member (not shown) using an edge part of the horizontal portion p as a rotation fulcrum.
A connector q is attached to a surface of the holder n having the opposite surface, to which the communication portion b is attached. Further, terminals r (only one of which is shown in FIG. 18) of the connector q are connected to the drive-unit-side connector m through the lands k, k, . . . , k of the transformer a and the second connection parts j, j, . . . , j.
Thus, for instance, when a tape cassette s is loaded into a loading portion of the drive unit, a holder n placed at a position (indicated by two-dot chain lines in FIG. 18), where the holder n does not interfere with the tape cassette s, at that time is rotated. Consequently, each of the terminals r, r, . . . , r, of the connector q are connected to the corresponding external terminal that is connected to the memory t included in the tape cassette s.
As a result of connecting the external terminals to the terminals r, r, . . . , r, of the connector q, the system is brought into a state in which information can be read from and written to the memory t through the connector q. Moreover, when the holder n is rotated in a direction, in which the holder n approaches the tape cassette s, and the external terminals connected to the memory t are further connected to the terminals r, r, . . . , r, of the connector q, the communication portion b of the transformer a and the memory t are held in such a way as to be at a predetermined distance. Furthermore, the system is put into a state, in which information can be read from and written to the memory t without bringing the connector into contact with the external terminal.
Meanwhile, in the case of the aforementioned transformer a, the connecting portion c is constituted by a flexible printed substrate so that when the holder n is rotated, the rotation operation is smoothly performed.
However, to enhance the sensitivity by increasing the number of turns of the coil portion g of the transformer circuit f, the communication portion b is formed as a multi-layer by stacking substrates d, d, . . . , d, whose base material is, for instance, an epoxy resin material.
Therefore, the thickness of the communication portion b increases for that. Consequently, the conventional transformer has a drawback in that a larger space is necessary for placing the communication portion b therein Further, the communication portion b and the connecting portion c are formed as different members respectively made of different materials. Thus, the conventional transformer has another drawback in that the number of parts is large and that number of steps of a manufacturing process is large.
Accordingly, an object of the present invention is to decrease the thickness of a transformer and the number of parts thereof without reducing the sensitivity thereof.
To achieve the foregoing object, according to an aspect of the present invention, there is provided a transformer formed as a multi-layer substrate by stacking a plurality of flexible printed substrates each having a predetermined circuit pattern.
Moreover, to achieve the foregoing object, according to the present invention, there is provided a cassette library system which comprises a transformer formed as a multi-layer substrate by stacking a plurality of flexible printed substrates each having a predetermined circuit pattern, and which reads information from and writes information to a memory t for storing predetermined information, which is mounted on a recording medium cassette, through a communication portion b without bringing an external terminal connected to the memory into contact with a connector connected to lands of the transformer.
Thus, according to the transformer and the cassette library system of the present invention, the thickness of the transformer and the number of parts are reduced.